1. Field of the Invention
The present invention generally relates to a traffic management system of a wide-area network (WAN) and in particular to a traffic monitor and traffic management system and method for use in a frame-relay or leased-line (dedicated-line) network.
2. Description of the Related Art
In general, a WAN system is composed of a frame-relay/leased-line network and a plurality of subscriber systems. Each of the subscriber systems is provided with a router that handles a plurality of subscriber lines. The router is connected to the frame-relay/leased-line network through a digital service unit (DSU) and a terminal adapter (TA).
In such a network, traffic management is one of the most important management items and therefore various traffic management techniques have been proposed. For example, a routing control system disclosed in Japanese Patent Application Unexamined Publication No. 6-132959 performs centralized management regarding routers and LANs so as to reduce the network traffic.
A frame-relay exchange disclosed in Japanese Patent Application Unexamined Publication No. 7-307762 is provided with a table for storing a priority of a received frame for each data link connection identifier (DLCI). When the congestion exceeds a predetermined degree, a received frame having no priority is discarded so as not to discard a received from having high priority.
Further, there has been disclosed a method for displaying a traffic state within a network in Japanese Patent Application Unexamined Publication No. 8-181771. According to this method, a management station performs both configuration management and performance management to display easy-to-understand traffic states between network elements.
Although these conventional techniques can be combined to achieve a proper traffic management, such a conventional traffic monitoring system does not provide a means for monitoring the traffic of permanent virtual connection (PVC), resulting in reduced flexibility in add-on design of the subscriber system.
Further, the conventional traffic monitoring system is designed to monitor the traffic at a point between the TA and the router connected to the subscriber system. Therefore, in the case of the router having the TA built therein, an additional TA is needed to convert V-series interface to I-series interface.
An object of the present invention is to provide a traffic monitor and traffic management system and method that can improve flexibility in add-on design of a subscriber system.
Another object of the present invention is to provide a traffic monitor and traffic management system and method that can monitor the traffic for each connection within the wide-area network.
According to the present invention, traffic within a wide-area network such as a frame-relay/leased-line network is monitored at a reference point T of user network interface. In other words, a traffic management system includes a traffic monitor for monitoring traffic at a reference point T of user network interface to produce traffic information for each connection, and further includes a traffic manager for managing network traffic of the wide-area network based on the traffic information received from the traffic monitor. The traffic information may be produced for each permanent virtual connection (PVC) or for each dedicated line.
The traffic monitor may be provided with a connector that is connected to a subscriber line at the reference point T and branches a transmission signal of the subscriber line to produce a branched transmission signal. The traffic monitor may be further provided with an interface device for detecting a frame from the branched transmission signal during a designated time period and a processor for producing the traffic information of predetermined traffic parameters for each connection based on frames detected for the designated time period.
The traffic information may be produced by counting the frames for each permanent virtual connection (PVC) or for each dedicated line during the designated time period for each dedicated line. The traffic information may be produced for each data link connection identifier (DLCI) included in an address field of a frame.